Materials Development and Design Effort for V/Li Blanket in Japan

Transcription

1 Materials Development and Design Effort for V/Li Blanket in Japan T. Muroga Fusion Engineering Research Center, National Institute for Fusion Science, Japan US/Japan Workshop on Power Plant Studies and Related Advanced Technologies Oct. 9 and 10, UCSD

2 V/Li Research in Japan Collaboration by Materials, Blanket and Design people is increasing on V/Li system in Japan Progress in the development of vanadium alloys by NIFS/Universities Enhanced development of Li technology in relation to IFMIF-Key Technology Development Enhanced participation to ITER-TBM by NIFS/ Universities, presently V/Li is the candidate being examined by NIFS/Universities MHD coating development needs collaboration with design group and the collaboration is being enhanced

3 Production and Characterization of High Purity V-4Cr-4Ti (NIFS-HEATs) NIFS-HEAT-1 has been tested by Japanese Universities NIFS-HEAT-2 was distributed for international collaboration April 98 FY1998 FY1999 FY2000 FY2001 FY2002 FY2003 Development of high purity V Development of alloying method NIFS-HEAT-1 (30 kg) Melting Shaping Test NIFS-HEAT-2 (166 kg) Melting Shaping Test (mm) 26t 6.6t 4.0t 1.9t 1.0t 0.5t 0.25t 10 cm 2d 8d NIFS-HEAT-2 ingots Products Specimens distributed

4 Merit of Purification Some properties (welding, working, radiation response (in limited cases)) were improved by reduction of O and N Feasibility of economical recycling was demonstrated by reducing Al, Nb, Ag, Mo Oxygen / wppm US-Ingot* US-V* JP-V V-4Cr-4Ti NIFS-HEAT-2 US-Plate* Dolan, 1994 NH1-Plate** NH1-Ingot NH2-Plate** NH2-Ingot US US NIFS-HEAT Remote Recycle limit (remote-control reprocessing) Quasi-Remote Recycle limit Quasi-Hands-on Recycle limit (contact reprocessing with some radiation control) Hands-on Recycle limit Nitrogen / wppm 0.1 Al Nb Ag Mo Element Al Nb Ag Mo Hand-on Limit (wppm)

5 Fabrication Technology (Tubing, welding) Plates, wires, tubes were successfully fabricated Good property of laserweldment T = 3 mm Specimen: 50 X 8 X 3 mm 2TR X 180 o N H m m, P re-heating Mandrel 3-directionalroll M achining Interm ediate annealing 1 mm 10 mm Initialpipe Absobed energy, E / J cm φ10 X 0.5t X 100 (mm) φ4.57 X 0.25t X 400 Laser welding, bead-on-plate E = 150 J cm -2 U E U / 2 As-weld NH2 plate Before weld NH2 plate 150 K Test temperature, T / K

6 Creep Properties of NIFS-HEAT One of the concerns by the purification was the creep strength Creep strength of NIFS-HEATs was similar to other V-4Cr-4Ti V-4Cr-4Ti V-15Cr-5Ti Creep Rupture T (log t + 20) F82H NIFS-HEATs Fukumoto (ICFRM-10) Significant progress was made in developing vanadium alloys with improved engineering maturity and feasibility for economical recycling

7 Status of V-Alloy Development Key-Issues Massive production high purity low activation Fabrication tech. Welding MHD coating Radiation effects(he) Feasibility almost demonstrated Progress being made but further efforts necessary for feasibility Systematic efforts necessary

8 IFMIF Key Technology Verification IFMIF Key Technology Verification studies were carried out in Japan in FY 2000~2002, sharing responsibility by JAERI and NIFS/Universities Li related Target research was carried out mainly NIFS/Universities IFMIF Schedule Key Element Technology Phase (KEP) Transition Engineering Validation and Engineering Design Activity (EVEDA) Construction 2010~2016 Operation 2017~ Accelerator Target Test Cell Beam-trip suppression RF source stability, efficiency Reduction of activation High power RFQ Cooling of CW DTL Injector RFQ DTL Li free surface control Impurity/tritium control Long life time Li flow D beam Heat Exchanger EM Pump Neutron irradiation Specimen Specimen temperature control Small specimen technology Remote handling Post-irradiation examination

9 Li Target Test (Osaka University) A test station was installed to 200L Li loop of Osaka Univ. for Target test Free surface test successfully carried out in FY2002 Li and relating device technologies were enhanced 1 m/s Li Li Experiment Station 14 m/s Horiike 2002

10 Li Impurity Control (U. Tokyo) V-10Ti and Cr were shown to be effective getter material for hot N trap Control of N is essential for T recovery with Y T recovery study with Y in progress (U. Tokyo, Kyushu U.) Ar S. Tanaka 2002 Li V-Ti Cr Mo Crucible Heater Nitrogen in Li [wppm] V-10Ti Cr Immersion time [ks] Nitrogen level in Li with Immersion Time at 823K

11 Li Loop Experiment Planned in EVEDA Full-size test loop will be constructed for validation of continuous operation Impurity control system will be installed based on KEP results The technology will be applied to Li blanket ~2 m ~8 m 5m/s 50L/s 250C Quench Tank EM Pump Dumptank nozzle 0.3 L/s, 250C Backwall ( R25cm) Li jet (20m/s) 600C V-Ti, Cr Hot Trap for N 550C Y Hot Trap for T 200C Cold Trap Li monitor H N O C R

12 ITER-TBM Past Proposals From Japan, only solid breeders were proposed to ITER via JAERI A NIFS-collaboration activity started in 2002, in which liquid blanket test module is explored Party Proposed TBM-type Party Proposed TBM-type JAPAN Solid - Water JAPAN Solid - Water Solid - Helium Solid - Helium EU Solid - Helium EU Solid - Helium Li-Pb - Water Li-Pb - Water Russia Solid - Helium Russia Solid - Helium Lithium Lithium US Solid - He Lithium

13 NIFS Collaboration Activity for ITER-TBM Li/V as a reference and Flibe as a back-up Support from JAERI First output expected in 2004 Subject University NIFS Initial Activity Thermalstructural Analysis Hashizume Horiike Takahashi Imagawa Nagasaka Thermal-structural analysis MHD-reduction Neutronics Iguchi T. Tanaka T-production Nuclear Heat, After Heat, Activation T-recovery S. Tanaka Fukada Suzuki Hot trap Cold trap Materials Matsui Abe Nagasaka Design data Flibe-module concept Terai Sagara Concept exploration Design Integration Matui JAERI Muroga Sagara Reporting

14 Roadmap for Materials and Blanket Development in Japan (Fast Option) Approximate calendar year Advanced Powerplant Design Power Generation Plant Design Construction Operation (Licencing) (Blanket test) ITER Blanket Module Test Materials and Blanket System Development Reference Material (RAFM) and System Advanced Materials (V-alloy, SiC/SiC --) and System IFMIF Irradiation Test, Materials Qualification and System Performance Test (Staged construction and operation) Fast Power Generation Option (Mostly JAERI responsibility) Advanced Option (Mostly NIFS/University responsibility)

15 Purpose of Li/V ITER-TBM (current discussion in NIFS collaboration) Feasibility of no-be and natural Li blanket Use of 7 Li reaction for enhancing TBR in contrast to Russian Be+ 6 Li enriched TBM Validation of neutronics prediction Technology integration for V-alloy, Li and T

16 ITER with Li/V self-cooled blanket - MCNP calculation by T. Tanaka (NIFS) - [ Inboard ] A SS, H 2 O Vacuum vessel 40 cm Blanket FW Plasma B SS (60%), Li coolant (40%) V-4Cr-4Ti walls, Natural Li Coil structure Vacuum vessel Blanket + Filler Center solenoid 1 m A : Standard ITEF-FEAT blanket B : ITER with V/Li full blanket A B FW 40 cm Blanket [ Outboard ] SS, SS, HH 2 O 2 O Vacuum vessel Input geometry for MCNP calculation * ( * Dimensions from ITER Nuclear Analysis Report) V-4Cr-4Ti walls, Natural Li SS (60%), Li coolan (40%)

17 Tritium production rate (g/fpd /cm 3 ) ITER with Li/V self-cooled blanket - Local TBR - 5.0x10-7 T otal 4.0x10-7 6L i 7L i 3.0x x x10-7 (a) Inboard Filler Blanket Li/V blanket Coolant in filler Total FW Position (cm ) Local TBR (Full Coverage) * Inboard Tritium production rate (g/f P D /cm 3 ) Outboard 5.0x10-7 FW T otal 4.0x10-7 6L i 7L i 3.0x x x (b) Outboard 0.0 Distribution of tritium production rate Significant contribution of 7 Li to TBR Total Blanket Contribution of 7 Li (%) ( * JENDL 3.2) Filler Position (cm )

18 Neutron spectrum at first wall of Standard and V/Li Blanket N eutron flux (n/cm 2 /s/lethargy) ITER-FEAT ITER-Li/V Neutron energy (M ev) C ross section for tritium production (barns) N eutron energy (M ev) 6L i(n,a) T 7L i(n,na) T Comparison of Neutron Flux at Outboard First Wall Cross Section for Tritium Production (JENDL 3.2) Significant difference between thermal neutron component in ITER-FEAT and ITER-Li/V Thermal neutron should be shielded in the TBM area of ITER-FEAT for the purpose of simulating V/Li blanket condition

19 Russian Li/V self-cooled test blanket module - Structure Be multiplier WC Shield (Reflector) 1720 (Unit : mm) Plasma V-5Cr-5Ti Li layer ( 6 Li : 90%) SS(60%) + H 2 O(40%) Structure of Russian Li/V TBM 6 Li enriched coolant (7.5 % ==> 90%) Li layer x 2, Be multiplier ==> 6 Li (n, α) T Maximize the 6 Li reaction to demonstrate DEMO reactor breeding tritium by 6 Li

20 Russian Li/V self-cooled test blanket module - Tritium production - Plasma Li/V TBM SUS + H 2 O SS316 TBM frame Tritium production rate (g/fpd /cm 3 ) TBM surface 1.0x10-5 T otalt P R 8.0x10-6 T P R from 6L i T P R from 7L i 6.0x x x10-6 Plasma Li layer (1) Li layer (2) Tritium production rate in Li layers and contribution of 6 Li and 7 Li Be WC SS+H 2 O Li layer (1) Li layer (2) [ 6 Li : 90%] Total : 0.09 (g/fpd) Position (mm)

21 1720 Tentative design of Li/V self-cooled TBM by NIFS/Universities Verification of (1) Coolant circulation (2) MHD coating Plasma V-4Cr-4Ti Verification of (1) Neutron transport (2) Tritium production from 7 Li Li layer SS(60%), H 2 O(40%) SS316 TBM frame (Unit : mm) Inlet/outlet pipes Li : ~0.027 m 3 Tentative design of Li/V TBM Plasma Li/V TBM SS(60%), H 2 O(40%) Verification of TPR for 7 Li Thick Li tanks for verification of neutron transport

22 Tentative design of Li/V self-cooled TBM - Tritium production - Plasma Covering by B 4 C SS(60%), H 2 O(40%) For verification of tritium production from 7 Li (n, nα)t reaction - Reduction of thermal neutrons by B 4 C shielding Li layer (1) Tritium production rate (g/f P D /cm 3 ) (2)(3)(4)(5) Li layer (1) Li layer (1) 4.0x10-6 N at.li N at.li+b4c (7.5m m ) 3.0x x x10-6 (2) (3) (4) (5) Position (mm) Tritium production rate in Li layers Contribution of 7 Li(%) (2) N at.l i N at.l i+b 4C (7.5m m ) (3) (4) (5) Position (m m ) Contribution of 7 Li to tritium production

23 Experimental parameter for Li/V TBM - Adjustment by B 4 C shield C ontribution of 7 Lito T P R (%) cm in front side Li/V TBM cm in rear side 10 cm in front side 40 Li/V blanket 10 cm in rear side 20 Russian TBM Thickness of B 4 C cover (mm) Changes in contribution of 7 Li by B 4 C covering Contribution of 7 Li to TPR can be adjusted by thickness of B 4 C shield

24 MHD Coating Necessity Duct Magnetic Field MHD Pressure Drop Force Li Flow Load to pumping system Force to structures Pressure Drop: proportional to Flow length Velocity B 2 Duct thickness Conductivity of Li and Duct Insulator coating inside the ducts a possible solution

25 MHD Coating Candidates (1) Free Energy V 2 O 5 Stable ceramics in a quite reducing condition Selection from the free energy data Li 2 O CaO Y 2 O 3 Er 2 O 3 CaZr(Sc)O 3 AlN BN x x /T (K) 3 x 10-3

26 MHD Coating Candidates (2) Bulk Compatibility Potential candidates Y 2 O 3 Er 2 O 3 AlN with N control CaZr(Sc)O 3 (~700C) others 10µm/y Japan-US JUPITER-II Collaboration (Pint, Suzuki et al. 2002)

27 MHD Coating Development Present Efforts Development of coating technology RF-sputtering EB-PVD Arc Plasma Deposition Characterization of the coating Resistivity High temperature stability Compatibility with Li Radiation induced conductivity In-situ coating technology RF-sputtering AlN coating (ohm*cm) RF-sputtering Y2O3 coating (ohm*cm) RF-sputtering Er2O3 coating (ohm*cm) Arc-P-Depo. Er2O3 coating (ohm*cm) by Dr. Fujiwara EB Depo. Y2O3 coatingtempdata2 (ohm*cm) by Dr. Pint Temp.(C) Minimum requirement Japan-US JUPITER-II Collaboration (Suzuki, Pint et al. 2003)

28 In-situ Coating The in-situ coating method has advantages as, possibility of coating on the complex surface after fabrication of component potentiality to heal the cracks without disassembling the component CaO coating has been explored V-alloy O v O 2 - Ca ++ M 2 O x Li(M) M Li M x +

29 Problems of the CaO Coating and New Effort on Er 2 O 3 It was found that the CaO coating, after formation, dissolved at high temperature (600, 700C) CaO bulk is inherently not stable in pure Li at high temperature, continuous supply of oxygen is necessary to maintain the coating Er 2 O 3 is much more stable at high temperature It is expected Er 2 O 3, once formed, be stable in Li for a long time Er 2 O 3 is stable in air, combination of dry-coating and in-situ coating is more feasible CaO Er2O3 10µm/y

30 In-situ Er 2 O 3 Coating on V-4Cr-4Ti Er 2 O 3 layer was formed on V-4Cr-4Ti by oxidation, anneal and exposure to Li (Er) at 600C The coating was stable to 300 hrs The resistivity was ~10 13 ohm-cm V-4Cr-4Ti Oxidation at 700C 6 hr Intensity x Oxidation only Er2O3-layer-0030_1.PRO O1s Er4d V2p3 Intensity x Oxidation and anneal at 700C for 16 hr ~100 nm Er2O3-layer-0035_1.PRO O1s Er4d V2p Sputter Time (min) Sputter Time (min) Er 1 hr Intensity x Er2O3-layer-0067_1.PRO O1s Er4d V2p3 Intensity x Er2O3-layer-0062_1.PRO O1s Er4d V2p Yao Sputter Time (min) Sputter Time (min) XPS depth profile after exposure to Li (Er) at 600C for 100 hr

31 Need for Collaboration with Design People Requirement to the coating performance depends strongly on the design System design is necessary to quantify the requirement to the coating Clever design would make the requirement lenient New idea of coating will be obtained by collaboration with design Laminar coating structure, etc.

32 Meeting Summary for Crack Fraction Allowance for the MHD Coating (Sze Aug.03) For a single pipe, with a perfect insulating coating, the allowable crack fraction was <10(-7) For a real coating, 10(-2) is achievable, while 10(-4) might be achievable. If we start with a poor coating, the allowable fraction can be higher, maybe 10(-4), with a higher MHD pressure drop. There are other ways to increase the allowable crack fraction, such as change the aspect ratio of the channel, change the boundary conditions of the flow channel. The boundary condition of the flow channel, such as the contact resistance between the fluid and the wall, may have major impact on the crack fraction. The change of the designs may have major impact on the crack allowance.

33 Impact of Sze Summary on the Coating Development in Japan Experimental examination of the resistance between the (flowing) Li and the wall covered with cracked coatings at high temperature is of high priority. The goal of the in-situ healing may be set to increase the resistivity of cracked area from complete conduction by 4 order of magnitude Allowable crack fraction : 10(-7) Realistic crack fraction : 10(-3) Increased collaboration between materials and design people in Japan

34 Design Effort to Reduce Requirement to the Coating Optimization of channel structure for reducing the requirement to the coating Coating may be necessary only on limited flat surfaces Insulator ribs may be inserted instead of coated ribs/walls Other suggestions on laminar coating structure, enhanced heat transfer, etc 5mm 805mm 205mm 5mm 0.625mm Model (a) (insulator ribs) Model (b)(+ coated back wall) 0.625mm 1mm (unit : kpa/m) σ insulator /σ HT Ideal case of (c) Model (a) Model (b) Model (c) Model (d) Model (c) Model (d) (coated ribs and back wall) ( + coated end ribs) (Hashizume)

35 Summary Collaboration by Materials, Blanket and Design people are increasing on V/Li system in Japan Progress in developing vanadium alloys toward engineering maturity Enhanced Li technology by IFMIF-KEP Increased accessibility for the liquid blanket people to ITER-TBR Collaboration on MHD-coating development by materials and design people One of the goals of the collaboration is to propose V/Li ITER-TBM The collaboration is enhancing research for other advanced blanket systems (Flibe --) The collaboration covering Material, Blanket and Design people in the US will accelerate the progress, and should be enhanced in the framework of JUPITER-II